week5:Chemical bonding, electronegativity, weak bonds

Question 1

What leads to the formation of chemical bonds?

Answer 1

The tendency of atoms to react with other atoms

Question 2

What is a covalent bond?

Answer 2

The bonding that occurs between two non-metals sharing their electrons.

Question 3

What is an ionic bond?

Answer 3

Transfer of electrons

Question 4

Only electrons involved in bonding are the?

Answer 4

Valence electrons

Question 5

What is the difference between Lewis dot symbol and electron configuration

Answer 5

electron configuration shows all the electrons in an atom. Lewis dot only shows the valence electrons.

Question 6

Why do chemical bonds form?

Answer 6

To obtain stability. Bounded atoms have a lower energy state thus, are more stable.

Question 7

State the octet rule.

Answer 7

When forming a chemical bond, an element loses, gains, or shares electron(s), in order to have 8 electrons in its outermost shell (or only 2 electrons for elements near He.

Question 8

What theory states that the driving force of covalent bond formation derives from the octet rule?

Answer 8

Valence bonding theory

Question 9

What is a non-polar covalent bond?

Answer 9

Covalent bonding between atoms with same electronegativity

Question 10

What is a polar covalent bond?

Answer 10

Covalent bonding between atoms with different electronegativity

Question 11

what determines bonding strength?

Answer 11

Attraction of bonding electrons by both nuclei

Question 12

where on the energy distance graph indicates bond length

Answer 12

minimum of energy

Question 13

What is molecular orbital

Answer 13

A new orbital that is formed to accommodate electrons from the atoms forming the molecule, a region where all their electrons are most likely to be found. It is a combination of atomic orbitals.

Question 14

How is the bonding interaction achieved in terms of molecular orbital

Answer 14

The bonding interaction is achieved because
the energy of the molecular orbital is lower
(more favorable) than the energy of the atomic
orbital

Question 15

What is a sigma molecular orbital?

Answer 15

Molecular orbitals that are symmetrical about
the axis of the bond (head to head overlap of
atomic orbitals)

Question 16

Molecular orbital theory predicts that:

Answer 16

The combination of two atomic orbitals leads to the formation of two molecular orbitals named bonding molecular orbital and antibonding molecular orbital

Question 17

Bonding molecular orbitals ?

Answer 17

have a lower energy than the atomic orbitals from which they were formed

Question 18

Anti-bonding orbitals?

Answer 18

they have a higher energy than the atomic orbitals from which they were formed

Question 19

Electrons occupy Anti-bonding molecular orbitals while bonding molecular orbitals remain empty, true or false?

Answer 19

False!!

Question 20

explain hybrid orbitals

Answer 20

https://www.youtube.com/watch?v=vHXViZTxLXo

Question 21

What is a coordinate (dative) covalent bond

Answer 21

A covalent bond between two atoms where one of the atoms provides both electrons for sharing
*refer lecture 2c

Question 22

how to calculate formal charge

Answer 22

formal charge=valence electrons - nonbonded electrons - 1/2 bonded electrons

Question 23

Describe the hydrogen bond

Answer 23

When hydrogen bonds to a highly electronegative atom causes the molecule to have a permanent dipole, in which hydrogen is partially postive, thus causing it to be attracted to other electronegative atoms

Question 24

What are some properties of hydrogen bonds?

Answer 24

Elevated boiling temperature
High values of latent heat of fusion and vaporization, specific heat capacity

Question 25

What are some biological significance of hydrogen bonding?

Answer 25

-Protein shaping
-Interaction between antibodies and antigen
-Hold complemenatry strands of DNA, participates in RNA three dimensional structure

Question 26

What are the types of van der Waals interactions?

Answer 26

-Dipoles (permanent dipole, instantaneous dipole, Induced dipole)
-London dispersion force-temporarily polar from a neighboring induced dipole